This application claims a priority benefit from German Application No. 100 27 389.0, filed on Jun. 2, 2000, and the contents on that priority application are incorporated herein by reference.
This invention concerns a process of synchronization of a signal by detection of synchronization patterns, for example in mobile wireless signals.
Mobile wireless signals are normally transmitted as bursts, with a synchronization sequence being transmitted in each burst that makes demodulation easier for the receiver during amplitude variations (fading) and multi-path reception and which allows an estimation of a channel pulse response. In this regard, either a fixed synchronization sequence is transmitted or a transmitted synchronization sequence is chosen from a limited number of possible synchronization sequences.
A test demodulator for such signals has the function of determining exactly a time relationship of the signals, measuring using a weighting filter and relating time-wise, with a high relative exactness, to the sent synchronization sequence. If a plurality of various synchronization sequences are transmitted, it must first be determined which synchronization sequence is present in a concrete, or definite, burst. In addition, a time-wise position of the synchronization sequence must be determined and an input signal is, if necessary for a particular case, time-wise shifted so that there is a defined time position of the input signal.
Normally, this is accomplished by having the input signal demodulated by an I/Q demodulator at the bit level and it is searched for the synchronization sequence at the bit level. In this manner, the relative time-wise position of the synchronization sequence within the input signal can be determined and the input signal can be accordingly shifted.
It is disadvantageous in this procedure that there is a relatively high calculation demand for demodulating data contents down to the bit level.
Accordingly, it is an object of this invention to provide a process for synchronization of a signal with a reduced calculation requirement.